1. Technical Field
The present invention relates in general to the field of electronic component testing and in particular to methods and apparatus for automatically testing electronic components during an assembly process. Still more particularly, the present invention relates to a method and apparatus for randomly selecting electronic components from a plurality of components and automatically testing the selected components.
2. Background Art
Electronic component testing devices are well known in the prior art. Many different manufacturers produce various meters and/or testing devices which may be utilized to accurately and easily determine whether or not a particular electronic component is within design specifications. While these test devices are entirely satisfactory for most applications, increasingly complex modern electronic devices require an enormous number of electronic components which must be tested during assembly to achieve a high degree of quality assurance.
Currently, the state-of-the-art in electronic device assembly is toward automated devices which are capable of positioning electronic components rapidly, accurately and without human intervention. A large number of such devices are known which are capable of repeatedly positioning very small electronic components on substrates or circuit boards utilizing robotics techniques. An effort is currently being made to advance the state of this art by means of machines capable of placing a plurality of electronic components on a substrate or circuit board simultaneously. For example, Panasonic National provides a system entitled "Panasert Simultaneous Chip Component Placement Machine Model No. NM8270." Another proposed system for simultaneously placing large numbers of electronic components onto substrates or printed circuit boards utilizes plastic carrier tubes which are loaded with large numbers of electronic components. An example of this type of system is disclosed in U.S. Pat. Application Ser. No. 07/155,945, filed Feb. 18, 1988, now abandoned, and assigned to the assignee hereof.
In each application in which many electronic components are to be mounted to a substrate or printed circuit board it is necessary to provide a method and apparatus to test large numbers of the electronic components so that system quality may be maintained. Those skilled in the quality assurance art will appreciate that while it is generally only necessary to test a small percentage of the total number of electronic components to be utilized in order to achieve a high level of quality, these modern systems utilize such astronomical numbers of electronic components that even a small percentage of the components can amount to a very large number. Thus, it should be apparent that manually testing these devices is not an effective manner of maintaining system quality in view of the large numbers of components involved. Therefore, a need exits for a method and apparatus which permits electronic components to be rapidly and randomly tested with a high degree of accuracy.